The increasing demand for high-speed voice and data communications has led to an increased reliance on optical communications, particularly optical fiber communications. The use of optical signals as a vehicle to carry channeled information at high speeds is preferred in many instances to carrying channeled information at other electromagnetic wavelengths/frequencies in media such as microwave transmission lines, co-axial cable lines and twisted pair transmission lines. Advantages of optical media are, among others, high-channel capacity (bandwidth), greater immunity to electromagnetic interference, and lower propagation loss. In fact, it is common for high-speed optical communication systems to have signal rates in the range of approximately several Giga bits per second (Gbit/sec) to approximately several tens of Gbit/sec.
One way of carrying information in an optical communication system, for example an optical network, is via an array of optical fibers. Ultimately, the optical fibers need to be terminated in a manner that permits connection of the fibers to other optical components such as optical sources or receivers. Typically, the optical components to which connection is made are located on rack-mounted boards. As rack space in fiber optic networking equipment becomes denser, board-to-board spacing in the racks becomes smaller, and connectivity to the closely spaced boards becomes increasingly difficult. No longer can connectors be placed facing the board surface so that the optical axis of the fiber is perpendicular to the board surface, because the fiber must be bent with too tight of a bend radius in order to fit in between closely spaced boards. The tight bend radius can be avoided by making connections at the edge of the board. However, edge connectivity can be limiting in several ways. Connecting to the edges of the boards not only limits the number of optical channels possible, but also forces the connectivity in an opposite direction most natural to the majority of the preferred datacom light sources and receivers, e.g., vertical-cavity surface-emitting laser (VCSEL) or PIN photodiode array. These preferred sources and receivers are surface plane devices, which are more prevalently used in networking applications today than older edge-emitting technologies. The surface plane devices need connectivity that leverages their vertical light input/output orientation. The vertical orientation introduces problems with connectivity, as explained above, because top-facing connectivity is not possible in racks where the board-to-board density is great. While additional components may be introduced to effect bending of the light from the vertical to horizontal direction, adding even one light bending component increases assembly complexity due to the requirement of optically aligning two interfaces instead of one. Moreover, the addition of a light bending component also increases yield loss and cost.
Accordingly, there exists a need for a relatively simple, inexpensive, fiber termination that leverages the electrical connection benefits of surface plane devices while not introducing extra components into the on-board package.